Home / The guide / Know-how

Food preservation

Preservation turns a harvest into a year of food, but mistakes can cause botulism. Learn tested methods from an expert source, not improvised ones.

How

1. Take a course: extension programmes such as Preserve@Home (University of Idaho, online) cover foodborne illness, boiling water canning for acid foods, pressure canning for low-acid foods, jams, pickles, fermentation, drying and freezing.
2. Print and follow the USDA Complete Guide to Home Canning (2015 revision), free as PDF files from the National Center for Home Food Preservation, with a printed edition from Purdue Extension (US).
3. Have dial pressure canner gauges tested every year; many US extension offices do this (Illinois Extension). Penn State Extension says to adjust a gauge that is off by less than 2 psi and replace one off by more than 2 psi.
4. Practise each method on small batches with an experienced person before scaling up. The how-to detail is in living-10 to living-13.
5. Outside the US, ask your national food safety agency or agricultural college for tested guidance; do not adapt recipes.

Safety: Only use tested recipes and processing times. Low-acid foods must be pressure canned (see living-10).

Do these first

• food-1

Sources

1. Preserve@Home course brochure (January 2026). University of Idaho Extension (hosted by Colorado State University Extension), accessed 2026-11
2. About the USDA Complete Guide to Home Canning, 2015 revision. National Center for Home Food Preservation (University of Georgia), accessed 2026-11
3. Free pressure canner testing. University of Illinois Extension, accessed 2026-11
4. Pressure canner dial gauge testing. Penn State Extension, accessed 2026-11

Open in the interactive guide